Disentangled ultra-high molecular weight polyethylene (UHMWPE) when subjected to specialized processing, yields polyethylene products having extremely high strength and modulus—a consequence which is attributed to the uniform and parallel orientation of the polymer chains of disentangled UHMWPE, when subject to processing techniques such as hot stretching. As a virtue of their characteristic physical properties, these extremely high strength polyethylene products have found abundant applications in diverse areas such as adventure sports, research laboratories, medical devices, aeronautical environments and the like.
Conventionally, traditional heterogeneous stereo-specific catalysts have been used in the preparation of UHMWPE, which is further used for preparing high strength polyethylene products. However, the UHMWPE that results, is present in a highly entangled state. The entangled nature of the polymer decreases the melt processability by conventional processing tools; thereby limiting the efficient preparation of the high strength products.
U.S. Pat. No. 4,436,689 and US Publication No. 2011/0207907 disclose a process known as gel spinning for preparing very high strength polyethylene products from entangled UHMWPE. The processes disclosed in the afore-stated prior art documents, however, essentially require a step of solvent removal which is expensive and time consuming. Also, in order to prepare films and tapes of very high strength from UHMWPE, the latter needs to be subjected to compression molding before rolling and hot stretching. For instance, the PCT document WO 2009/153318 discloses a process for the preparation of very high strength polyethylene product that includes the process steps of compacting the UHMWPE, followed by rolling, followed by hot stretching. This not only makes the process more expensive and time consuming, but also lowers the efficiency of the overall process. Furthermore, the process disclosed in the PCT document WO 2009/153318 professes heating the UHMPWE powder before dosing which necessitates more energy and time input.
Therefore, there is a need to develop a process for the preparation of high strength products of UHMWPE that reduces the drawbacks of the prior art processes.